Apparatus is already known in the packaging field which operates discontinuously or continuously and is designed to supply blanks of packaging material in individual sequence by taking up these blanks, which may be of the type having a flat folded tubular structure, stacked or disposed side by side in a hopper store, and erecting this type of blank with a flat tubular structure during its extraction from the store for the supply stage by means of an operation to expand it into its tubular shape so that it can receive the product or products to be packaged.
In the case of continuously moving apparatus in this specific technological field of packaging, operating speeds tend to be increasingly greater with the passage of time as a result of refinements to the structures designed to cause the mechanisms with suction components, which are continuously rotated for the take up of the blanks from the store, to have the necessary steps. These structures, designed to cause these mechanisms with suction take up components rotated continuously in order to enable the take up of the blanks from the store to pause, substantially comprise a support wheel provided with a continuous rotary movement bearing one or more simple articulated systems (articulated quadrilaterals) projecting from its periphery, one of its rods (rocker arm) being structured, for example, in an elastically telescopic manner with its articulation on the bridge of the quadrilateral articulated loosely, the articulation of the opposite rod or rocker arm on this bridge being formed as a double cam follower operating alternately in the cycle (see British Patent Specification No. 1 017 056).
In practice, the articulated quadrilateral structures operated in this way, although causing the respective mechanisms with suction take up members to pause (these members having a reciprocating motion perpendicular to the plane in which the blanks lie in the fixed store for the take up of the corresponding blank from the store during their displacement with a continuous movement), to some extent limit the unit operating speed of these supply apparatus. Attempts to simplify the structure of these articulated quadrilaterals in order to increase the unit operating speed of these supply apparatus by constructing the articulation on the bridge of the cam follower rod or rocker arm with a single cam follower and leaving the structure and the articulation on the bridge of the opposite, simply articulated, rod unchanged, have not in practice made it possible to implement the required pause with the correspondingly required reciprocating movement of the relative mechanism with a component for taking up the blanks from the store (see British Patent Specification No. 3 053 133).